Enhanced shear-induced platelet aggregation due to low-temperature storage

Area of Science:

• Hematology
• Biophysics
• Transfusion Medicine

Background:

• Platelet (PLT) storage at room temperature poses risks of bacterial contamination and limits shelf life.
• Refrigeration (4°C) offers potential benefits but alters PLT function and reduces in vivo circulation time.
• The impact of refrigeration on PLT hemostatic function under varying shear conditions requires further characterization.

Purpose of the Study:

• To investigate the effects of 2-day refrigeration on platelet (PLT) hemostatic function.
• To assess PLT aggregation, activation, and von Willebrand factor (VWF) binding under physiologic and pathophysiologic shear conditions.
• To evaluate changes in glycoprotein (GP) Ibα expression and ristocetin-induced PLT agglutination after refrigeration.

Main Methods:

• Washed platelets were prepared from fresh or 4°C-stored platelet-rich plasma (PRP).
• Platelets were mixed with VWF and fibrinogen, then subjected to shear stress in a cone-and-plate viscometer.
• Measurements included PLT aggregation, activation, VWF binding, GP Ibα expression, and ristocetin-induced PLT agglutination.

Main Results:

• Refrigerated platelets exhibited significantly increased aggregation at high shear rates compared to fresh platelets.
• Shear-induced PLT activation and VWF binding were greater in refrigerated platelets.
• GP Ibα expression was lower, and ristocetin-induced PLT agglutination was modestly decreased in refrigerated platelets.

Conclusions:

• Refrigeration enhances platelet aggregation and VWF binding under high shear, but not static, conditions.
• Increased shear-induced platelet aggregation after refrigeration may offer a clinical benefit for managing bleeding in trauma.
• Low-temperature storage strategies warrant further investigation for optimizing platelet transfusion efficacy.